This invention relates to an electrode assembly for a surgical instrument for the treatment of tissue, particularly an electrosurgical endoscopic instrument. Such systems are commonly used for the vaporisation and/or coagulation of tissue in surgical intervention, most commonly in “keyhole” or minimally invasive surgery.
One type of electrosurgical procedure is endoscopic urological surgery using a resectoscope. Such systems are well known in the art, examples being given in U.S. Pat. Nos. 5,007,907 and 6,322,494. Such systems include an electrosurgical instrument deployable by means of a resectoscope, and an electrosurgical generator powering the instrument. Instruments used in electrosurgical urology surgery are either bipolar, in which case two electrodes are present at the distal end of the instrument, or monopolar, in which case one electrode is present on the instrument and a second electrode is provided in the form of a patient return plate.
Bladder tumour resection is often difficult due to the curved shape of the tissue, and the fact that there is no clear dissection plane visible to the surgeon. Deviating from the ideal depth of tissue removal either means that insufficient tissue is removed, or the too much tissue is removed, including the possibility of perforating the bladder.